Ready Player One was a lot of fun. I read it maybe a year after it came out, and along with the intentionally retro elements, the whole book felt like it came from an earlier time. The notion of the internet becoming a "virtual world" may have been a big part of it. As someone who explored Second Life and MMOs in the mid-aughts, the whole idea just has a "futures past" feel to it, like the cigar-shaped rockets and "homes of the future" of the mid-20th-century. It just seemed like a future someone would have imagined in the late '90s or early aughts.

Granted, it was more a wild flight of fantasy than anything genuinely speculative